Managing IP Addresses

Updated: July 22, 2009

Applies To: Windows SBS 2008, Windows Small Business Server 2011 Standard

Using a static Internet IP addresses

The Internet IP address is set on the external network port on your router. If you need to set or change a static Internet IP address on your router, you must change it in the router management console. For information about how to access the router management console from the Windows SBS Console, see the “Configure your router” section in “Managing Your Windows Small Business Server 2008 Network” at the Microsoft Web site (https://go.microsoft.com/fwlink/?LinkID=115881). For information about how to configure your router, see the documentation for your router manufacturer.

Changing the local IP address on the server

During installation, Windows SBS 2008 searches for a router. If it finds a router that has a valid IP address, Windows SBS 2008 configures the local network adapter on the server with a static IP address in the same range as the router. For example, if the router’s internal network port IP address is 192.168.1.1, then the server’s IP address is 192.168.1.2. All network-related services are set up to use IP addresses in the same range.

If you do not want to use the IP address that is assigned during installation to the server that is running Windows SBS 2008, you can change the IP address in the Local Area Connection Properties for the server network adapter, and then run the Fix My Network Wizard to ensure that all network services use the new IP address. For information about running the wizard, see the “Run the Fix My Network Wizard” section in “Managing Your Windows Small Business Server 2008 Network” at the Microsoft Web site (https://go.microsoft.com/fwlink/?LinkID=115881).

If you want to change the subnet that is assigned during installation to the server that is running Windows SBS 2008, you can change the static IP address to a new subnet on the internal network adapter on the router, and then run the Connect to the Internet Wizard. For example, if your local network is currently using subnet 192.168.0 and you want it to use 192.168.1, change the IP address on the internal network adapter on the router to 192.168.1.1. When you run the Connect to the Internet Wizard, the network adapter on the server is assigned 192.168.1.1 IP address, and all network services are configured use the new IP address. For information about running the wizard, see the “Connecting to the Internet” section in “Managing Your Windows Small Business Server 2008 Network” at the Microsoft Web site (https://go.microsoft.com/fwlink/?LinkID=115881).

Using IPv6

During Windows SBS 2008 installation, a static Internet Protocol version 6 (IPv6) address is automatically configured on the server. Because many applications are programmed to use IPv4, Windows SBS 2008 runs IPv4 and IPv6 on the same network, either wired or wireless. Windows SBS 2008 also configures DHCP and DNS for IPv6. For the server to use IPv6 to reach the Internet, Windows SBS 2008 is expecting that a stateless, auto-configured IPv6 router connects your local network to the Internet. You can disable IPv6, if you prefer.

Using reverse DNS

DNS resolves a known domain name or host name to an IP address. Reverse DNS resolves a known IP address to a domain name or a host name. For example, if you want to know the host name for the IP address 192.168.1.2, you use reverse DNS, which can resolve the address to server.contoso.com.

One of the applications of reverse DNS on the Internet is to act as a spam filter. For example, reverse DNS would recognize if a malicious user is using an IP address that is not valid and does not resolve to a domain name. A reverse DNS lookup program checks the IP addresses of incoming messages against a DNS database. If no valid name matches the IP address, the server blocks that message.

Most Internet service providers (ISPs) support reverse DNS when you purchase a static IP address from them. To help your e-mail messages get through spam filters, contact your ISP to set up reverse DNS for your domain name.